Select custfirst, custlast, 
         first_order_id,
         first_orderdate,
         first_order_total_items,
         first_order_total_cost
         last_orderdate, 
         last_order_id,
         last_orderdate,
         last_order_total_items,
         last_order_total_cost
         
from custmer where 
  
     custid in (select max(orderdate) as last_orderdate from orders group by custid, orderdate order by orderdate DESC) OR
     custid in (select min(orderdate) as first_orderdate from orders group by custid, orderdate) 

with FOrders
as (
 select CustId
  ,Ro = Row_Number() over (
   partition by CustId order by OrderDate asc
   )
  ,FirstOrderId = OrderId
  ,FirstOrderDate = OrderDate
 )
 ,LOrders
as (
 select CustId
  ,Ro = Row_Number() over (
   partition by CustId order by OrderDate desc
   )
  ,LastOrderId = OrderId
  ,LastOrderDate = OrderDate
 )
select c.CustId
 ,FOrders.FirstOrderDate
 ,FOrders.FirstOrderId
 ,LOrders.LastOrderDate
 ,LOrders.LastOrderId
 ,
from Customer c
left join FOrders on c.CustId = FOrders.CustId
left join LOrders on c.CustId = LOrders.CustId
where (
  FOrders.ro = 1
  or FOrders.ro is null
  )
 and (
  LOrders.ro = 1
  or LOrders.ro is null
  )

CREATE TABLE #Customer
    (CustID VARCHAR(10)
    ,OrderDate DATETIME)

INSERT INTO #Customer
SELECT 'A', '2012-01-31' UNION ALL SELECT 'A', '2012-03-31' UNION ALL SELECT 'A', '2012-05-15'
UNION ALL SELECT 'B', '2012-03-31' UNION ALL SELECT 'B', '2012-05-31' UNION ALL SELECT 'B', '2012-07-15'

SELECT CustID, OrderDate -- Include other fields you want returned here
FROM (
    SELECT CustID, OrderDate -- Include other fields you need here
        ,a=MIN(OrderDate) OVER (PARTITION BY CustID)
        ,b=MAX(OrderDate) OVER (PARTITION BY CustID)
    FROM #Customer) a
WHERE a = OrderDate OR b = OrderDate

DROP TABLE #Customer